Sonoscan has shipped the first of its new D9600Z C-SAM systems. This new model is designed expressly to facilitate the imaging of IGBT (Insulated Gate Bipolar Transistor) power modules.
Power modules, such as IGBTs, are basically high-speed high-power switches used in railway engines, electric automobiles, and many other applications involving high power. Prior to packaging the transistors themselves are at the top of the module and are too susceptible to water contact to permit acoustic imaging from above.
Sonoscan has developed a WaterPlume transducer that scans through the heat sink from the bottom of the module. Ultrasound pulsed into the heat sink will also image ceramic plates (rafts) above the heat sink, and even the die attachments near the top of the module.
To speed imaging, the D9600Z has an option for two transducers that operate simultaneously. Each transducer is coupled with the surface of the heat sink by a constant stream of upward-flowing water that touches only the heat sink. Air knives built into the system dry the heat sink after scanning.
The stage of the D9600Z is supplied with various plates designed to hold common IGBT module configurations. The operation is fully automated: the operator places the module on the stage, closes the door, and pushes a button.
The targets of interest include voids in the solder above the heat sink, the flatness of ceramic plates, and voids in the die attach material. The system can also measure and map the thickness of the solder layer during scanning.
The D9600Z is a quick, nondestructive tool to analyze IGBT power modules, which are typically costly and destined for critical applications.